Acoustic collection devices comprising funnels, elongated tubes and/or listening bells have been used for centuries. As is relevant herein, acoustic collection devices can generally be considered to fall into two categories: (1) stethoscopes for close-range, contact-based sound transmission, and (2) funnels used for contactless, longer range sound detection and amplification, such as parabolic collectors.
The first medical stethoscope is attributed to the nineteenth century French physician René Laennec. Stethoscopes have since come to be used ubiquitously not only by doctors, but also by scientists and craftsmen in a broad range of fields that have a need for basic sound conduction/amplification. The modern stethoscope consists of a chestpiece having a hollow stem connected to a length of hollow tubing that leads to two earbuds.
The chestpiece typically consists of two opposite sides, one having a diaphragm that transmits higher frequency sounds, and the other side having a rigid, cupped bell for transmitting lower frequency sounds. The standard stethoscope includes a semi-rigid frame that serves the dual purpose of mounting the ear buds and allowing the stethoscope to hang around the user's neck.
For longer-range, contactless sound collection, funnels are often used. Though no longer in widespread use, ear trumpets were traditionally used to assist people with hearing nearby conversation or sounds. Modernly, parabolic microphones have come into ubiquitous use for gathering sound waves traveling over distances as great as several hundred yards. The design of a parabolic microphone is fairly straightforward: a cone with a parabolic inner wall focuses incoming sound waves at the geometric focal point of the parabola. A microphone is mounted at the focal point to collect the sound. Alternatively, a tube with an opening may be placed at the focal point, and the sound conducted through the tube to a listening location.
In the present disclosure, the generic term “acoustic collector” or “collector” will be used to refer to acoustic collectors in the nature of both (1) stethoscope chestpieces and (2) longer-range, contactless sound collectors, such as funnels and parabolic collectors. These longer-range, contactless acoustic collectors may also be referred to as “open air” collectors because they are not pressed against a surface in the manner of a stethoscope chestpiece. Where the term “stethoscope chestpiece” or “chestpiece” is employed, it should be noted that although this disclosure will use those terms to refer to a unit containing a diaphragm and/or a bell, such a unit need not only be used in conjunction with medical evaluations. The “chestpiece” might also be used for any number of applications that benefit from being able to detect sound vibrations through a material. The size and shape of the chestpiece might also vary, along with the type and sensitivity of the diaphragm and/or bell. As used herein, “chestpiece” refers broadly to any unit having a surface for resting against a sound-transmitting material, and a hollow interior for transmitting that sound out through a stem.
With the advent of handheld electronic devices, some have proposed alternative designs for stethoscopes that call for incorporating them with electronic sound recorders and wireless transmitters. For example, it has been proposed to attach a stethoscope chestpiece to an electronic recording device mounted along the tube running to the stethoscope's earbuds. This “in-line” device may be equipped with a microphone and Bluetooth-type transmitter for wirelessly delivering a sound recording.
It has also been proposed that a small stethoscope diaphragm be built into the back of a cellular phone. This design is of limited use, however, because, it would require manufacturing a cellular telephone with a small diaphragm already “embedded” into main body of the phone. This is a specialty-purpose application that most cellular phone manufacturers would not consider. Furthermore, embedding a small diaphragm within the phone limits its size.
Another proposed solution is to physically connect a tube from the chestpiece to the microphone of a cellular phone. Such a design proposes that a phone have a microphone at one end, and that an adapter connects the stethoscope tube directly to the end of the phone equipped with the microphone. These proposals call for the chestpiece to be physically separate from the main body of the electronic device, and in some cases connected only by a long length of tubing. The disadvantages of such proposals include at least: (1) instability of the mounting, (2) difficulty of handling the portable electronic device and the chestpiece as separate items, and (3) poor sound quality and conduction.